Simplified: HP tx series batteries lineup (tx1000/2000/2500)

There's a 4-cell, a 6-cell, and an 8-cell.
The 6-cell came with my custom ordered machine, and the 4-cell and 8-cell came with my premade "tx2551xx"

HP Parts Surfer
4 cell Part #441131-003 on HP Part Surfer not found on HP Shopping.
6 cell Part #441132-003 on HP Part Surfer or RQ204AA on HP Shopping
8 cell Part #463650-003 on HP Part Surfer or KC991AA on HP Shopping